Understanding the interactions of the cytokines of the immune system in the regulation of the immune cascade host-defense mechanism is of intense scientific interest. Newly emerging research a]so demonstrates that some of these molecules act in an endocrine fashion outside the immune system. Examining these molecules as circulating endocrine communicating signals offers new scientific challenges, but these challenges have been significantly impeded by the lack of simple, reliable assay systems to evaluate these molecules in biologic fluids of experimental animals. Assay Research's human cytokine immunoassays detect these molecules in serum, where other immunoassays do not. In addition, little or no attention has been focused on supporting basic cytokine research with analytical systems that evaluate murine cytokines in culture media, as well as serum. The goal of this contract is to develop a complete battery of fully validated murine cytokine enzyme immunoassays, with specific technology that deals with limited sample amounts from these animals.